D31.02 - Wet Blue

SIGNIFICANCE AND USE
5.1 This test method is designed to determine the temperature at which the Wet Blue or Wet White specimen experiences shrinkage. In this test method, shrinkage occurs as a result of hydrothermal denaturation of the collagen protein molecules which make up the fiber structure of the Wet Blue or Wet White. The shrinkage temperature of Wet Blue or Wet White is influenced by many different factors, most of which appear to affect the number and nature of crosslinking interactions between adjacent polypeptide chains of the collagen protein molecules. The value of the shrinkage temperature of Wet Blue or Wet White is commonly used as an indicator of the type of tannage or the degree of tannage, or both, of that particular Wet Blue or Wet White (especially for the more hydrothermally stable tannages such as chrome tannage).
SCOPE
1.1 This test method covers the determination of the shrinkage temperature of all types of Wet Blue and Wet White. The heating medium is water when the shrinkage temperature is at or below 98 °C. The heating medium is a glycerine-water solution when the shrinkage temperature is above 98 °C.  
1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 This test method enumerates proteolytic bacteria. Proteolytic bacteria have been known to cause damage to hides and skins.
SCOPE
1.1 This test method covers the enumeration of bacteria that can hydrolyze protein/collagen in fresh (uncured) hides and skins. This test method is applicable to uncured hides and skins.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 This test method enumerates salt tolerant (halophilic) bacteria, and proteolytic bacteria that are also salt tolerant. Under the conditions of this test method those bacteria are equated as halophilic organisms. Salt tolerant proteolytic bacteria have been known to cause damage to hides and skins in raceway brine.
SCOPE
1.1 This test method covers the enumeration of bacteria that can tolerate high salt concentrations or can hydrolyze protein/collagen, or both. This test method is applicable to raceway brine, brine-cured hides and skins, and pre-charge raceway liquor.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 This test method measures the amount of unfixed chrome in Wet Blue. Results may vary according to the age of the Wet Blue.
SCOPE
1.1 This test method covers the procedures to analyze and calculate unfixed chrome concentrations in Wet Blue.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The procedure described is for chromium in Wet Blue using Atomic Absorption or ICP. This method may be used to determine the chromium content in Wet Blue as an alternate to Test Method D6656.  
5.2 The chromium content of Wet Blue is related to the degree of tannage obtained, and hence may be a matter for specification in the purchase of Wet Blue. The procedure described provides adequate accuracy for this purpose.
SCOPE
1.1 This test method covers the Atomic Absorption procedure, using nitrous oxide-acetylene flame, air-acetylene flame or ICP (Inductively coupled plasma) to analyze the chrome content of Wet Blue (and leather) on a moisture-free basis.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Some specific hazards statements are given in Section 9 on Hazards and in 12.5 and 12.20.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
6.1 The environmental chamber method is an accelerated test for determining the resistance of Wet Blue and Wet White to the growth of fungi, the causal agent of mold. See Test Method D3273.3,4  
6.2 The environmental chamber method is useful in estimating the performance of fungicides and should assist in the prediction of storage time before fungal growth begins.  
6.3 The environmental chamber method duplicates the natural environment in which Wet Blue or Wet White is inoculated with fungal spores and subsequently disfigured or discolored by fungi.  
6.4 The environmental chamber method measures the resistance of the treated Wet Blue or Wet White to the germination of spores and subsequent vegetative growth that spreads over the surface of a comparatively large Wet Blue or Wet White specimen over a period of four weeks.  
6.5 The environmental chamber can be kept inoculated with fungi representative of those found in tanneries by adding samples of Wet Blue and Wet White with fungal growth from currently operating tanneries.  
6.6 Control specimens of Wet Blue and Wet White without fungicide treatment can be added to the chamber periodically to increase levels of fungal growth in the chamber.  
6.7 Leaching of fungicide from the test specimen into the agar often causes a zone of inhibition of fungal growth in the Petri dish test, but in the environmental chamber any leaching of fungicide from the test specimen drips into the water contained in the chamber and thus does not cause the types of false readings observed in the Petri dish test.
SCOPE
1.1 This environmental chamber method measures the resistance of the treated Wet Blue and Wet White to the germination of spores and subsequent vegetative growth over a period of four weeks. The test method is useful in estimating the performance of fungicides and should assist in the prediction of storage time of Wet Blue and Wet White before fungal growth begins. The apparatus is designed so it can be easily built or obtained by any interested party and duplicate the natural environment in which Wet Blue and Wet White is inoculated with fungal spores. Spores that germinate on untreated or treated Wet Blue and Wet White can produce fungal growth, resulting in disfigurement or discoloration, or both, of the Wet Blue and Wet White.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 This test method is designed to measure the pH of a distilled-water extract of Wet Blue and Wet White. This is considered to be a measure of the acidity or alkalinity of the Wet Blue or Wet White. Excessive acidity or alkalinity may have a deleterious effect on the aging characteristics of Wet Blue and Wet White and the leather made from it.  
4.2 This test method is suitable for development, control, and service evaluation of wet blue.
SCOPE
1.1 This test method covers the determination of the pH of all types of Wet Blue and Wet White.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 This test method enumerates yeast and mold. Yeast and mold have been known to cause damage to hides and skins.
SCOPE
1.1 This test method covers the enumeration of yeast and mold on fresh (uncured) hides and skins. This test method is applicable to uncured hides and skins.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 This test method measures the amount of solvent-soluble (hexane or petroleum ether) materials in wet blue and wet white.
SCOPE
1.1 This test method covers the quantitative extraction of all types of wet blue and wet white with hexane or petroleum ether.  
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement, see Section 7.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The procedure described is specific for chromium in Wet Blue. Vanadium is the only common interfering element and is rarely present in quantity. The precision and accuracy of the methods are usually, at least, as good as the sampling of Wet Blue itself.  
5.2 The chromium content of Wet Blue is related to the degree of tannage obtained, and hence may be a matter for specification in the purchase of Wet Blue. The procedure described provides adequate accuracy for this purpose.
SCOPE
1.1 This test method covers the determination of chromic oxide in Wet Blue that has been partly or completely tanned with chromium compounds. In general, the samples will contain chromium content between 1 % and 5 % when calculated as chromic oxide expressed upon a dry basis otherwise referred to as moisture-free basis (mfb).  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This test method does not apply to Wet White.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. See Section 9 for specific safety hazards.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 This test method provides a technique for evaluating mold growth resistance characteristics of Wet Blue and Wet White, and should assist in the prediction of storage time before molding occurs.  
4.2 The degree of correlation between this test and commercial quantities of Wet Blue and Wet White in storage or shipment situations, or both, has not been fully determined.
SCOPE
1.1 This test method covers the determination of mold growth resistance of Wet Blue and Wet White subject to storage and shipping requirements and intended for use in leather manufacturing. This test method may not be suitable to evaluate fungicides that are inactivated by proteins. This includes alkyldimethylbenzyl ammonium chlorides.  
1.2 Conclusions about mold growth resistance are drawn from the results by comparing the test with a simultaneously run control of known resistance. Success or failure is determined by the amount of mold growth relative to the control.  
1.3 To allow use of this test method by any laboratory, flexibility has been permitted in times, temperature, and humidity of incubation, inoculum, hide sampling area, and choice of control. These may be adjusted to fit local conditions but must be standardized.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 Determination of the hydro-thermal area stability of Wet Blue provides information concerning the efficacy of the tanning process as well as the adequacy of the Wet Blue for intended end use applications where area stability is a particular requirement. Relative area stability of chrome-tanned leather is a requirement for many applications such as bookbinding, shoe and boot components, upholstery, seals and gaskets, etc.  
4.2 This test method is suitable for use in development work and process control in the tannery and for specification testing of Wet Blue for domestic and international commercial purposes.
SCOPE
1.1 This test method provides a standard procedure for determination of the dimensional stability or area shrinkage of a specimen of Wet Blue that is submersed in boiling water for a specified time period. This test method is applicable to all types of Wet Blue.  
1.2 The values given in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.  
1.3 This test method does not apply to Wet White.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 The sampling procedures described in this practice have been designed to ensure random sampling of Wet Blue and Wet White for physical and chemical tests. Wet Blue and Wet White are natural products and as such are subject to extensive variability. The physical and chemical properties vary considerably depending on location on the hide, side, or skin from which the test sample is taken. Random sampling of specimens from a predefined location and orientation minimizes test bias and variability. This practice defines these parameters.
SCOPE
1.1 This practice covers the sampling and preparation of Wet Blue and Wet White for physical and chemical tests. The product is grouped into lots that are randomly sampled in such a manner as to produce a representative sample of the lot. This sample may be used to determine compliance of the lot with applicable specification requirements, and on the basis of results, the lot may be accepted or rejected in its entirety.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 The procedure described is specific for chromium in Wet Blue. Vanadium is the only common interfering element and this is rarely present in quantity. The precision and accuracy of the methods are usually at least as good as the sampling of the Wet Blue itself, and the accuracy of previously performed test methods.  
5.2 The chromium content of Wet Blue is related to the degree of tannage obtained, and hence may be a matter for specification in the purchase of Wet Blue. The procedure described provides adequate accuracy for this purpose.
SCOPE
1.1 This test method covers the determination of chromic oxide in Wet Blue that has been partly or completely tanned with chromium compounds. In general the samples will contain chromium content between 1 and 5 %, calculated as chromic oxide expressed upon a dry basis otherwise referred to as moisture-free basis (mfb).  
1.2 This test method is specific in that it applies to a sample or samples that are the resultant ash following the execution of Test Method D6716.  
1.3 This test method does not apply to Wet White.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific hazards are given in Section 8.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 This test method enumerates salt tolerant yeast and mold, and under the conditions of this test method those are equated as halophilic organisms. Salt tolerant yeast and mold have been known to cause damage to hides and skins in raceway brine.
SCOPE
1.1 This test method covers the enumeration of yeast and mold. This test method is applicable to raceway brine, brine-cured hides and skins, and pre-charge raceway liquor.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 This test method is useful in determining the approximate amount of nonvolatile inorganic material in wet blue. This may be in the form of salts or oxides of the elements. In a mixed-chrome tannage, the approximate percentage of other elements in the wet blue may be determined by subtracting the chromic oxide that may be conveniently determined on the ash. (See Test Method D6714.)  
5.2 The specified temperature of 600°C is high enough to produce a reproducible result but it does not completely dehydrate such oxides as aluminum oxide (Al2O3) and chromic oxide (Cr2O3). Likewise, such salts as sulfates and phosphates may be incompletely dehydrated, and if alkalis and chromium are present simultaneously, oxidation to chromate may occur. Therefore, caution is advised in drawing conclusions based on quantitative relations of the elements.
SCOPE
1.1 This test method covers the determination of total ash in wet blue and wet white.  
1.2 For total ash in wet white, the procedure is identical; substitute wet white for wet blue in the standard.  
1.3 Total ash in wet blue may be reported upon a number of different bases (for example, fat-free, moisture-free, as received, excluding chromium, and so forth). Before proceeding with any tests, it is very important to determine upon which basis that the total ash is to be reported and to identify all other test methods that will be required to be executed in order to achieve the determined reporting method.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 This test method is intended to evaluate whether sufficient salt (NaCl) has been retained by the hides or skins to slow down degradation by bacterial (enzymatic) action, and to slow down autolysis by inherent enzymatic action, until they are preserved by a tanning process.
Note 2: Osmosis occurs during brine curing because moisture is drawn out by salt through the epidermis.4 Low moisture (
SCOPE
1.1 This test method covers the estimation of degree of saturation of the brine content of cured (salt-preserved) hides and skins containing 40 % or more moisture.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 The result obtained by this test is normally considered to be the moisture content of the wet blue or wet white sample. This result is used to correct all other chemical tests to a moisture-free basis.  
4.2 Materials that are volatile under these conditions, other than water, may be present in the wet blue, although their amount in any normal wet blue would be expected to be a very small percentage of the total volatile matter.  
4.3 Under the conditions of this test, certain materials in wet blue, such as protein fiber and chromium tanning salts, may retain moisture. Other materials, such as natural animal fats, may be oxidized. Both of these effects produce negative errors in the moisture determination.  
4.4 The amount of volatile matter (moisture) released by a given sample varies with (a) method and time of sample preparation, (b) weight of sample taken, (c) temperature and time of the oven drying, (d) type of oven (gravity versus mechanical convection) used.  
4.5 Because of the above unknown errors, the result of this test is a purely arbitrary value for the moisture content of the sample. It is, therefore, essential that the method be followed exactly in order to obtain reproducible results among laboratories. This is particularly true if other chemical analytical tests being performed on the same sample are reported on the moisture-free basis.
SCOPE
1.1 This test method covers the determination of volatile matter (moisture) in all types of wet blue and wet white.  
1.2 This test method was originally developed for wet blue, however, this test method can be used to test wet white. For wet white testing, substitute the term wet white for wet blue in the standard.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
3.1 The sampling procedures described in this practice have been designed to ensure random sampling of salt-preserved hides and skins for physical and chemical tests. Fresh or salt-preserved hides are natural products and as such are subject to extensive variability. The physical and chemical properties vary considerably depending on location on that specific hide, side, or skin from which the test sample is taken. Random sampling of specimens from a predefined location and orientation minimizes test bias and variability. This practice defines these parameters.  
3.2 In general, tests carried out upon fresh or salt-preserved hides require composite lot samples generated using the preparation methods described within this practice. Subsequent tests typically require those composite samples to be in two forms:  
3.2.1 Expressed Hide Fluid—where residual hide fluid is pressed from cleaned individual hair-on or de-haired hide sample, then equal volumes of each extracted fluid are blended together to create the composite sample.
Note 1: Sample may be de-haired prior to pressing.  
3.2.2 Hide Material Sample—where equal quantities of cleaned hair-on or de-haired hide material are blended together to create a representative composite sample.
Note 2: Samples may be de-haired prior to compositing.
SCOPE
1.1 This practice covers the sampling and preparation of fresh or salt-preserved (cured) hides for physical and chemical tests. The hides or skins to be tested are grouped into lots. Each lot is randomly sampled in such a manner as to produce a representative sample of that lot. This lot sample may be used to determine compliance of the lot with applicable specification requirements, and on the basis of results, the lot may be accepted or rejected in its entirety.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 This test method enumerates proteolytic bacteria. Proteolytic bacteria have been known to cause damage to hides and skins.
SCOPE
1.1 This test method covers the enumeration of bacteria that can hydrolyze protein/collagen in fresh (uncured) hides and skins. This test method is applicable to uncured hides and skins.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 This test method enumerates salt tolerant (halophilic) bacteria, and proteolytic bacteria that are also salt tolerant. Under the conditions of this test method those bacteria are equated as halophilic organisms. Salt tolerant proteolytic bacteria have been known to cause damage to hides and skins in raceway brine.
SCOPE
1.1 This test method covers the enumeration of bacteria that can tolerate high salt concentrations or can hydrolyze protein/collagen, or both. This test method is applicable to raceway brine, brine-cured hides and skins, and pre-charge raceway liquor.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
5.1 This test method is designed to determine the temperature at which the Wet Blue or Wet White specimen experiences shrinkage. In this test method, shrinkage occurs as a result of hydrothermal denaturation of the collagen protein molecules which make up the fiber structure of the Wet Blue or Wet White. The shrinkage temperature of Wet Blue or Wet White is influenced by many different factors, most of which appear to affect the number and nature of crosslinking interactions between adjacent polypeptide chains of the collagen protein molecules. The value of the shrinkage temperature of Wet Blue or Wet White is commonly used as an indicator of the type of tannage or the degree of tannage, or both, of that particular Wet Blue or Wet White (especially for the more hydrothermally stable tannages such as chrome tannage).
SCOPE
1.1 This test method covers the determination of the shrinkage temperature of all types of Wet Blue and Wet White. The heating medium is water when the shrinkage temperature is at or below 98°C. The heating medium is a glycerine-water solution when the shrinkage temperature is above 98°C.  
1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

SIGNIFICANCE AND USE
4.1 This test method enumerates yeast and mold. Yeast and mold have been known to cause damage to hides and skins.
SCOPE
1.1 This test method covers the enumeration of yeast and mold on fresh (uncured) hides and skins. This test method is applicable to uncured hides and skins.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 The procedure described is specific for chromium in Wet Blue. Vanadium is the only common interfering element and this is rarely present in quantity. The precision and accuracy of the methods are usually at least as good as the sampling of the Wet Blue itself, and the accuracy of previously performed test methods.  
5.2 The chromium content of Wet Blue is related to the degree of tannage obtained, and hence may be a matter for specification in the purchase of Wet Blue. The procedure described provides adequate accuracy for this purpose.
SCOPE
1.1 This test method covers the determination of chromic oxide in Wet Blue that has been partly or completely tanned with chromium compounds. In general the samples will contain chromium content between 1 and 5 %, calculated as chromic oxide expressed upon a dry basis otherwise referred to as moisture-free basis (mfb).  
1.2 This test method is specific in that it applies to a sample or samples that are the resultant ash following the execution of Test Method D6716.  
1.3 This test method does not apply to Wet White.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazards are given in Section 8.

SIGNIFICANCE AND USE
4.1 This test method enumerates proteolytic bacteria. Proteolytic bacteria have been known to cause damage to hides and skins.
SCOPE
1.1 This test method covers the enumeration of bacteria that can hydrolyze protein/collagen in fresh (uncured) hides and skins. This test method is applicable to uncured hides and skins.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 The procedure described is for chromium in Wet Blue using Atomic Absorption. This method may be used to determine the chromium content in Wet Blue as an alternate to Test Method D6656.  
5.2 The chromium content of Wet Blue is related to the degree of tannage obtained, and hence may be a matter for specification in the purchase of Wet Blue. The procedure described provides adequate accuracy for this purpose.
SCOPE
1.1 This test method covers the Atomic Absorption procedure, using nitrous oxide-acetylene flame, to analyze the chrome content of Wet Blue on a moisture-free basis.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Some specific hazards statements are given in Section 9 on Hazards and in 12.5.

SIGNIFICANCE AND USE
4.1 This test method enumerates salt tolerant yeast and mold, and under the conditions of this test method those are equated as halophilic organisms. Salt tolerant yeast and mold have been known to cause damage to hides and skins in raceway brine.
SCOPE
1.1 This test method covers the enumeration of yeast and mold. This test method is applicable to raceway brine, brine-cured hides and skins, and pre-charge raceway liquor.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 This test method enumerates salt tolerant (halophilic) bacteria, and proteolytic bacteria that are also salt tolerant. Under the conditions of this test method those bacteria are equated as halophilic organisms. Salt tolerant proteolytic bacteria have been known to cause damage to hides and skins in raceway brine.
SCOPE
1.1 This test method covers the enumeration of bacteria that can tolerate high salt concentrations or can hydrolyze protein/collagen, or both. This test method is applicable to raceway brine, brine-cured hides and skins, and pre-charge raceway liquor.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 Determination of the hydro-thermal area stability of Wet Blue provides information concerning the efficacy of the tanning process as well as the adequacy of the Wet Blue for intended end use applications where area stability is a particular requirement. Relative area stability of chrome-tanned leather is a requirement for many applications such as bookbinding, shoe and boot components, upholstery, seals and gaskets, etc.  
4.2 This test method is suitable for use in development work and process control in the tannery and for specification testing of Wet Blue for domestic and international commercial purposes.
SCOPE
1.1 This test method provides a standard procedure for determination of the dimensional stability or area shrinkage of a specimen of Wet Blue that is submersed in boiling water for a specified time period. This test method is applicable to all types of Wet Blue.  
1.2 The values given in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.  
1.3 This test method does not apply to Wet White.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 The procedure described is specific for chromium in Wet Blue. Vanadium is the only common interfering element and is rarely present in quantity. The precision and accuracy of the methods are usually, at least, as good as the sampling of Wet Blue itself.  
5.2 The chromium content of Wet Blue is related to the degree of tannage obtained, and hence may be a matter for specification in the purchase of Wet Blue. The procedure described provides adequate accuracy for this purpose.
SCOPE
1.1 This test method covers the determination of chromic oxide in Wet Blue that has been partly or completely tanned with chromium compounds. In general, the samples will contain chromium content between 1 % and 5 % when calculated as chromic oxide expressed upon a dry basis otherwise referred to as moisture-free basis (mfb).  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This test method does not apply to Wet White.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See Section 9 for specific safety hazards.

SIGNIFICANCE AND USE
6.1 The environmental chamber method is an accelerated test for determining the resistance of Wet Blue and Wet White to the growth of fungi, the causal agent of mold. See Test Method D3273.3,4  
6.2 The environmental chamber method is useful in estimating the performance of fungicides and should assist in the prediction of storage time before fungal growth begins.  
6.3 The environmental chamber method duplicates the natural environment in which Wet Blue or Wet White is inoculated with fungal spores and subsequently disfigured or discolored by fungi.  
6.4 The environmental chamber method measures the resistance of the treated Wet Blue or Wet White to the germination of spores and subsequent vegetative growth that spreads over the surface of a comparatively large Wet Blue or Wet White specimen over a period of four weeks.  
6.5 The environmental chamber can be kept inoculated with fungi representative of those found in tanneries by adding samples of Wet Blue and Wet White with fungal growth from currently operating tanneries.  
6.6 Control specimens of Wet Blue and Wet White without fungicide treatment can be added to the chamber periodically to increase levels of fungal growth in the chamber.  
6.7 Leaching of fungicide from the test specimen into the agar often causes a zone of inhibition of fungal growth in the Petri dish test, but in the environmental chamber any leaching of fungicide from the test specimen drips into the water contained in the chamber and thus does not cause the types of false readings observed in the Petri dish test.
SCOPE
1.1 This environmental chamber method measures the resistance of the treated Wet Blue and Wet White to the germination of spores and subsequent vegetative growth over a period of four weeks. The test method is useful in estimating the performance of fungicides and should assist in the prediction of storage time of Wet Blue and Wet White before fungal growth begins. The apparatus is designed so it can be easily built or obtained by any interested party and duplicate the natural environment in which Wet Blue and Wet White is inoculated with fungal spores. Spores that germinate on untreated or treated Wet Blue and Wet White can produce fungal growth, resulting in disfigurement or discoloration, or both, of the Wet Blue and Wet White.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 This test method provides a technique for evaluating mold growth resistance characteristics of Wet Blue and Wet White, and should assist in the prediction of storage time before molding occurs.  
4.2 The degree of correlation between this test and commercial quantities of Wet Blue and Wet White in storage or shipment situations, or both, has not been fully determined.
SCOPE
1.1 This test method covers the determination of mold growth resistance of Wet Blue and Wet White subject to storage and shipping requirements and intended for use in leather manufacturing. This test method may not be suitable to evaluate fungicides that are inactivated by proteins. This includes alkyldimethylbenzyl ammonium chlorides.  
1.2 Conclusions about mold growth resistance are drawn from the results by comparing the test with a simultaneously run control of known resistance. Success or failure is determined by the amount of mold growth relative to the control.  
1.3 To allow use of this test method by any laboratory, flexibility has been permitted in times, temperature, and humidity of incubation, inoculum, hide sampling area, and choice of control. These may be adjusted to fit local conditions but must be standardized.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 This test method is designed to determine the temperature at which the Wet Blue or Wet White specimen experiences shrinkage. In this test method, shrinkage occurs as a result of hydrothermal denaturation of the collagen protein molecules which make up the fiber structure of the Wet Blue or Wet White. The shrinkage temperature of Wet Blue or Wet White is influenced by many different factors, most of which appear to affect the number and nature of crosslinking interactions between adjacent polypeptide chains of the collagen protein molecules. The value of the shrinkage temperature of Wet Blue or Wet White is commonly used as an indicator of the type of tannage or the degree of tannage, or both, of that particular Wet Blue or Wet White (especially for the more hydrothermally stable tannages such as chrome tannage).
SCOPE
1.1 This test method covers the determination of the shrinkage temperature of all types of Wet Blue and Wet White. The heating medium is water when the shrinkage temperature is at or below 98°C. The heating medium is a glycerine-water solution when the shrinkage temperature is above 98°C.  
1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 The sampling procedures described in this practice have been designed to ensure random sampling of Wet Blue and Wet White for physical and chemical tests. Wet Blue and Wet White are natural products and as such are subject to extensive variability. The physical and chemical properties vary considerably depending on location on the hide, side, or skin from which the test sample is taken. Random sampling of specimens from a predefined location and orientation minimizes test bias and variability. This practice defines these parameters.
SCOPE
1.1 This practice covers the sampling and preparation of Wet Blue and Wet White for physical and chemical tests. The product is grouped into lots that are randomly sampled in such a manner as to produce a representative sample of the lot. This sample may be used to determine compliance of the lot with applicable specification requirements, and on the basis of results, the lot may be accepted or rejected in its entirety.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 This test method is designed to measure the pH of a distilled-water extract of Wet Blue and Wet White. This is considered to be a measure of the acidity or alkalinity of the Wet Blue or Wet White. Excessive acidity or alkalinity may have a deleterious effect on the aging characteristics of Wet Blue and Wet White and the leather made from it.  
4.2 This test method is suitable for development, control, and service evaluation of wet blue.
SCOPE
1.1 This test method covers the determination of the pH of all types of Wet Blue and Wet White.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 The procedure described is specific for chromium in wet blue. Vanadium is the only common interfering element and this is rarely present in quantity. The precision and accuracy of the methods are usually at least as good as the sampling of the wet blue itself, and the accuracy of previously performed test methods.  
5.2 The chromium content of wet blue is related to the degree of tannage obtained, and hence may be a matter for specification in the purchase of wet blue. The procedure described provides adequate accuracy for this purpose.
SCOPE
1.1 This test method covers the determination of chromic oxide in wet blue that has been partly or completely tanned with chromium compounds. In general the samples will contain chromium content between 1 and 5 %, calculated as chromic oxide expressed upon a dry basis otherwise referred to as moisture-free basis (mfb).  
1.2 This test method is specific in that it applies to a sample or samples that are the resultant ash following the execution of Test Method D6716.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazards are given in Section 8.

SIGNIFICANCE AND USE
6.1 The environmental chamber method is an accelerated test for determining the resistance of wet blue to the growth of fungi, the causal agent of mold. See Test Method D3273.3,4  
6.2 The environmental chamber method is useful in estimating the performance of fungicides and should assist in the prediction of storage time before fungal growth begins.  
6.3 The environmental chamber method duplicates the natural environment in which wet blue is inoculated with fungal spores and subsequently disfigured or discolored by fungi.  
6.4 The environmental chamber method measures the resistance of the treated wet blue to the germination of spores and subsequent vegetative growth that spreads over the surface of a comparatively large wet blue specimen over a period of four weeks.  
6.5 The environmental chamber can be kept inoculated with fungi representative of those found in tanneries by adding samples of wet blue with fungal growth currently operating tanneries.  
6.6 Control specimens of wet blue without fungicide treatment can be added to the chamber periodically to increase levels of fungal growth in the chamber.  
6.7 Leaching of fungicide from the test specimen into the agar often causes a zone of inhibition of fungal growth in the Petri dish test, but in the environmental chamber any leaching of fungicide from the test specimen drips into the water contained in the chamber and thus does not cause the types of false readings observed in the Petri dish test.
SCOPE
1.1 This environmental chamber method measures the resistance of the treated wet blue to the germination of spores and subsequent vegetative growth over a period of four weeks. The test method is useful in estimating the performance of fungicides and should assist in the prediction of storage time of wet blue before fungal growth begins. The apparatus is designed so it can be easily built or obtained by any interested party and duplicate the natural environment in which wet blue is inoculated with fungal spores. Spores that germinate on untreated or treated wet blue can produce fungal growth, resulting in disfigurement or discoloration, or both, of the wet blue.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 The sampling procedures described in this practice have been designed to ensure random sampling of wet blue for physical and chemical tests. Wet blue is a natural product and as such is subject to extensive variability. The physical and chemical properties vary considerably depending on location on the hide, side, or skin from which the test sample is taken. Random sampling of specimens from a predefined location and orientation minimizes test bias and variability. This practice defines these parameters.
SCOPE
1.1 This practice covers the sampling and preparation of wet blue for physical and chemical tests. The product is grouped into lots that are randomly sampled in such a manner as to produce a representative sample of the lot. This sample may be used to determine compliance of the lot with applicable specification requirements, and on the basis of results, the lot may be accepted or rejected in its entirety.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 The procedure described is specific for chromium in wet blue. Vanadium is the only common interfering element and is rarely present in quantity. The precision and accuracy of the methods are usually, at least, as good as the sampling of wet blue itself.  
5.2 The chromium content of wet blue is related to the degree of tannage obtained, and hence may be a matter for specification in the purchase of wet blue. The procedure described provides adequate accuracy for this purpose.
SCOPE
1.1 This test method covers the determination of chromic oxide in wet blue that has been partly or completely tanned with chromium compounds. In general, the samples will contain chromium content between 1 % and 5 % when calculated as chromic oxide expressed upon a dry basis otherwise referred to as moisture-free basis (mfb).  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See Section 9 for specific safety hazards.

SIGNIFICANCE AND USE
5.1 The procedure described is specific for chromium in wet blue. Vanadium is the only common interfering element and is rarely present in quantity. The precision and accuracy of the methods are usually, at least, as good as the sampling of wet blue itself.  
5.2 The chromium content of wet blue is related to the degree of tannage obtained, and hence may be a matter for specification in the purchase of wet blue. The procedure described provides adequate accuracy for this purpose.
SCOPE
1.1 This test method covers the determination of chromic oxide in wet blue that has been partly or completely tanned with chromium compounds. In general, the samples will contain chromium content between 1 % and 5 % when calculated as chromic oxide expressed upon a dry basis otherwise referred to as moisture-free basis (mfb).  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See Section 9 for specific safety hazards.

SIGNIFICANCE AND USE
4.1 This test method is designed to measure the pH of a distilled-water extract of wet blue. This is considered to be a measure of the acidity or alkalinity of the wet blue. Excessive acidity or alkalinity may have a deleterious effect on the aging characteristics of wet blue and the leather made from it.  
4.2 This test method is suitable for development, control, and service evaluation of wet blue.
SCOPE
1.1 This test method covers the determination of the pH of all types of wet blue and wet white.  
1.2 For pH of wet white, the procedure is identical, substitute wet white for wet blue in the standard method.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 This test method measures the amount of solvent-soluble (hexane or petroleum ether) materials in wet blue and wet white.
SCOPE
1.1 This test method covers the quantitative extraction of all types of wet blue and wet white with hexane or petroleum ether.  
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement, see Section 7.

SIGNIFICANCE AND USE
4.1 This test method is designed to measure the pH of a distilled-water extract of wet blue. This is considered to be a measure of the acidity or alkalinity of the wet blue. Excessive acidity or alkalinity may have a deleterious effect on the aging characteristics of wet blue and the leather made from it.  
4.2 This test method is suitable for development, control, and service evaluation of wet blue.
SCOPE
1.1 This test method covers the determination of the pH of all types of wet blue and wet white.  
1.2 For pH of wet white, the procedure is identical, substitute wet white for wet blue in the standard method.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 This test method is designed to measure the pH of a distilled-water extract of wet blue. This is considered to be a measure of the acidity or alkalinity of the wet blue. Excessive acidity or alkalinity may have a deleterious effect on the aging characteristics of wet blue and the leather made from it.  
4.2 This test method is suitable for development, control, and service evaluation of wet blue.
SCOPE
1.1 This test method covers the determination of the pH of all types of wet blue and wet white.  
1.2 For pH of wet white, the procedure is identical, substitute wet white for wet blue in the standard method.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 This test method measures the amount of solvent-soluble (hexane or petroleum ether) materials in wet blue and wet white.
SCOPE
1.1 This test method covers the quantitative extraction of all types of wet blue and wet white with hexane or petroleum ether.  
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific hazard statement, see Section 7.

SIGNIFICANCE AND USE
5.1 The procedure described is specific for chromium in wet blue. Vanadium is the only common interfering element and is rarely present in quantity. The precision and accuracy of the methods are usually, at least, as good as the sampling of wet blue itself.  
5.2 The chromium content of wet blue is related to the degree of tannage obtained, and hence may be a matter for specification in the purchase of wet blue. The procedure described provides adequate accuracy for this purpose.
SCOPE
1.1 This test method covers the determination of chromic oxide in wet blue that has been partly or completely tanned with chromium compounds. In general, the samples will contain chromium content between 1 % and 5 % when calculated as chromic oxide expressed upon a dry basis otherwise referred to as moisture-free basis (mfb).  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See Section 9 for specific safety hazards.

SIGNIFICANCE AND USE
4.1 This test method provides a technique for evaluating mold growth resistance characteristics of wet blue, and should assist in the prediction of storage time before molding occurs.  
4.2 The degree of correlation between this test and commercial quantities of wet blue in storage or shipment situations, or both, has not been fully determined.
SCOPE
1.1 This test method covers the determination of mold growth resistance of wet blue and wet white subject to storage and shipping requirements and intended for use in leather manufacturing. This test method may not be suitable to evaluate fungicides that are inactivated by proteins. This includes alkyldimethylbenzyl ammonium chlorides.  
1.2 Conclusions about mold growth resistance are drawn from the results by comparing the test with a simultaneously run control of known resistance. Success or failure is determined by the amount of mold growth relative to the control.  
1.3 To allow use of this test method by any laboratory, flexibility has been permitted in times, temperature, and humidity of incubation, inoculum, hide sampling area, and choice of control. These may be adjusted to fit local conditions but must be standardized.  
1.4 For mold growth resistance of wet white, the procedure is identical, substitute wet white for wet blue in the standard method.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
4.1 The result obtained by this test is normally considered to be the moisture content of the wet blue or wet white sample. This result is used to correct all other chemical tests to a moisture-free basis.  
4.2 Materials that are volatile under these conditions, other than water, may be present in the wet blue, although their amount in any normal wet blue would be expected to be a very small percentage of the total volatile matter.  
4.3 Under the conditions of this test, certain materials in wet blue, such as protein fiber and chromium tanning salts, may retain moisture. Other materials, such as natural animal fats, may be oxidized. Both of these effects produce negative errors in the moisture determination.  
4.4 The amount of volatile matter (moisture) released by a given sample varies with (a) method and time of sample preparation, (b) weight of sample taken, (c) temperature and time of the oven drying, (d) type of oven (gravity versus mechanical convection) used.  
4.5 Because of the above unknown errors, the result of this test is a purely arbitrary value for the moisture content of the sample. It is, therefore, essential that the method be followed exactly in order to obtain reproducible results among laboratories. This is particularly true if other chemical analytical tests being performed on the same sample are reported on the moisture-free basis.
SCOPE
1.1 This test method covers the determination of volatile matter (moisture) in all types of wet blue and wet white.  
1.2 This test method was originally developed for wet blue, however, this test method can be used to test wet white. For wet white testing, substitute the term wet white for wet blue in the standard.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
5.1 This test method is useful in determining the approximate amount of nonvolatile inorganic material in wet blue. This may be in the form of salts or oxides of the elements. In a mixed-chrome tannage, the approximate percentage of other elements in the wet blue may be determined by subtracting the chromic oxide that may be conveniently determined on the ash. (See Test Method D6714.)  
5.2 The specified temperature of 600°C is high enough to produce a reproducible result but it does not completely dehydrate such oxides as aluminum oxide (Al2O3) and chromic oxide (Cr2O3). Likewise, such salts as sulfates and phosphates may be incompletely dehydrated, and if alkalis and chromium are present simultaneously, oxidation to chromate may occur. Therefore, caution is advised in drawing conclusions based on quantitative relations of the elements.
SCOPE
1.1 This test method covers the determination of total ash in wet blue and wet white.  
1.2 For total ash in wet white, the procedure is identical; substitute wet white for wet blue in the standard.  
1.3 Total ash in wet blue may be reported upon a number of different bases (for example, fat-free, moisture-free, as received, excluding chromium, and so forth). Before proceeding with any tests, it is very important to determine upon which basis that the total ash is to be reported and to identify all other test methods that will be required to be executed in order to achieve the determined reporting method.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

SIGNIFICANCE AND USE
3.1 The sampling procedures described in this practice have been designed to ensure random sampling of salt-preserved hides and skins for physical and chemical tests. Fresh or salt-preserved hides are natural products and as such are subject to extensive variability. The physical and chemical properties vary considerably depending on location on that specific hide, side, or skin from which the test sample is taken. Random sampling of specimens from a predefined location and orientation minimizes test bias and variability. This practice defines these parameters.  
3.2 In general, tests carried out upon fresh or salt-preserved hides require composite lot samples generated using the preparation methods described within this practice. Subsequent tests typically require those composite samples to be in two forms:  
3.2.1 Expressed Hide Fluid—where residual hide fluid is pressed from cleaned individual hair-on or de-haired hide sample, then equal volumes of each extracted fluid are blended together to create the composite sample.Note 1—Sample may be de-haired prior to pressing.  
3.2.2 Hide Material Sample—where equal quantities of cleaned hair-on or de-haired hide material are blended together to create a representative composite sample.Note 2—Samples may be de-haired prior to compositing.
SCOPE
1.1 This practice covers the sampling and preparation of fresh or salt-preserved (cured) hides for physical and chemical tests. The hides or skins to be tested are grouped into lots. Each lot is randomly sampled in such a manner as to produce a representative sample of that lot. This lot sample may be used to determine compliance of the lot with applicable specification requirements, and on the basis of results, the lot may be accepted or rejected in its entirety.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.